Another Useful HT Clutch Mod

Discussion in 'Frame Mounted Engines' started by AussieSteve, Dec 16, 2009.

  1. AussieSteve

    AussieSteve Active Member

    On the clutch side of things, found a great improvement today. On the semi-circular bottom edge of the clutch pivot lever, I rounded off the contact edge to about 0.5mm-0.8mm depth and smoothed the flat surface of the contact area of the semi-circular section. Smoothing the contact area of the bucking bar also helps.
    Grinders etc. only, don't bother trying with a file - it's hard.
    N.B. 'Bucking Bar' is a Chinese factory term, not mine.

    My idea was that the clutch separates more than is really necessary when disengaged, and that by rounding, (narrowing), the edge of the pivot, the (fully disengaged) plate separation would decrease, but feel and leverage would increase.
    Works beautifully.
    Along with that, by loosening/tightening the (clover nut) adjustment until the clutch just disengages when pinned, so that the clutch take-up happens when the lever is about half-way out, the clutch feels normal.
    The overall difference has to be felt to be believed.
    Almost like a nice, light, Honda clutch.
    Love these minor mods. Cost: 0$ (Just right.)

    ...Steve

    A sketch. Hope you can understand what I mean:-
    [​IMG]
     

    Attached Files:

    Last edited: Dec 16, 2009
    FurryOnTheInside likes this.

  2. Ghost0

    Ghost0 Guest

    I have always wanted to try this. I thought it would do exactly what you describe. Just haven't had the time.
     
  3. AussieSteve

    AussieSteve Active Member

    Worth the effort, Jim.
    After about 100km, when I looked at the end of the bucking bar, (for the uninitiated, the Chinese manufacturers' term for the short rod that, along with a ball bearing, disengages the clutch), there were a number of grooves where the pivot had cut into the b.bar. This causes much of the typical resistance when the clutch is pulled in. Smoothing the contact face and the corner, along with the top surface of the b.bar, makes an enormous difference. Case hardening would be even better - the pivot is pretty hard, (hard to file), but the b.bar is m.s., I think. (Very easy to file.)
    (A bit of oil on the clutch cable and no sharp bends doesn't go astray, either, along with relocating the clutch arm to be more square with the cable adjuster.)
    Who needs the fancy roller setup I've seen described?
    I can pull the clutch in with one finger now, and I'm a 110lb. weakling.

    The only thing to be careful of is to not make the pivot too narrow. If it rotates to 90ยบ the clutch could lock in the disengaged position. (The clutch works best with a fair bit of slack anyway, so that clutch take-up occurs when the lever is about half out, like a real bike.):-

    [​IMG]

    Thanks again for the studs,
    ... Steve
     

    Attached Files:

    Last edited by a moderator: Dec 18, 2015
  4. snowbanana

    snowbanana Member

    my clutch in nearly impossible to pull. I have not rounded off the edge yet but is it normal for the clutch to be so hard when stock? are there any adjustments that I could do to make it easier?
     
  5. AussieSteve

    AussieSteve Active Member

    Hello snowbanana, these clutches are horrible, off the shelf, aren't they?

    #1 - Trickle some oil into the clutch cable - the difference is worth the effort and of course, your cable will last longer. Lubricate everything on these kits.
    I remove the cable from the hand-lever, then add a few drops every now and then until I get a drop at the other end.
    The other way is to form a small funnel from thin cardboard and tape it to the top of the cable, then put some oil into the funnel and let it run in.

    #2 - Do the smoothing as recommended - again, the difference is worth it.

    #3 - Remove the RHS side-cover and very lightly grease the primary gears, then remove the LHS countershaft cover, remove the pin from the centre of the countershaft and put a small amount of grease into the hole. Replace the pin and put a dab of grease on the end of it, then make sure that the cam pivot in the side-cover is well greased. Re-assemble - done.

    #4 - Al.Fisherman has a clutch roller setup that will increase leverage still further, until you can disengage the clutch with one pinky. I'll try to find the link, otherwise, PM Al.Fisherman.

    Found it:- For Sale..Clutch roller bracket for HT

    ... Steve
     
    Last edited: Jan 16, 2010
  6. snowbanana

    snowbanana Member

    I saw a clutch roller on large philipino's thread and it looks like a good. I will do all of steps above and see how it goes.
     
  7. snowbanana

    snowbanana Member

    Do you think tri-flow would be a good oil?
     
  8. AussieSteve

    AussieSteve Active Member

    At the risk of sounding ignorant, what's 'tri-flow'?

    ... Steve
     
  9. snowbanana

    snowbanana Member

    Its just a lubricant oil that people use for skateboard bearings, bike chains etc. I think it should work well.
     
  10. AussieSteve

    AussieSteve Active Member

    Sounds good. For cable lubrication, I don't think that the type of oil is too critical. Anything that will flow into the cable-casing should do.
    I use a bit of my cheap lawnmower 2-stroke oil for cables and chains.

    ... Steve
     
  11. GearNut

    GearNut Active Member

    Tri-Flow is great for cables and hinges 'n stuff. Just do not try to use it to lubricate the ball bearing that is behing the "bucking bar". That NEEDS a good quality grease.

    P.S. Tri-flow is an all purpose light duty lubricant fortified with teflon.
     
  12. snowbanana

    snowbanana Member

    thanks for all of the tips.
     
  13. AussieSteve

    AussieSteve Active Member

    While fitting my shift kit, I noticed that the (reasonably soft) clutch push-rod, (bucking bar), still had slight marks from the edge of the pivot cam digging in. The push-rod is a bit soft, out of the box. This is part of the reason that the clutch is so hard to pull in.
    To try to alleviate this, I smoothed and polished the rod end, then heated the rod to cherry-red and quenched it in cold water to temper it a little more. Also did a bit more smoothing and polishing on the cam edge.
    I'll report on success/failure after a few rides.

    ... Steve
     
    Last edited: Jan 29, 2010
  14. Crobo

    Crobo New Member

    i had a question about where the grinding was done.

    the schematic drawn is a top view of the pin that the clutch lever turns. the rounded section is where the pin contacts the "bucking bar" that oushes through the center of the main drive gear.
     
  15. AussieSteve

    AussieSteve Active Member

    Here's a sketch. The original was a bit 'sketchy' - no pun intended:-
    (Thanks Crobo, for pointing it out.)

    [​IMG]

    Regarding hardening the bucking-bar, I had limited success. It's definitely better than before, but still isn't hard enough.
    A piece of old drill bit, ground down and polished to suit, appears much better. The hard metal of a drill bit isn't damaged by the pivot cam.
     

    Attached Files:

    Last edited: Mar 25, 2010
  16. nathanl

    nathanl New Member

    Wow! It seriously took me more time to readjust my clutch cable than it did to grind the pivot cam with a dremel! I had always been annoyed that no matter how I adjusted my clutch cable it never quite worked right with the little lock out button on the lever. This completely fixed that! Thanks!
     
  17. how hard is it to get the pivot cam out?
     
  18. AussieSteve

    AussieSteve Active Member

    Easy. With the side-cover removed, rotate the pivot and when in the right position it will slip right out. (There's a locating pin in the side-cover that engages a groove in the pivot.)
     
  19. Al.Fisherman

    Al.Fisherman Active Member

    Last edited: Jul 15, 2010
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